I. Field of the Invention
This invention relates to monitoring a patient's metabolic need over time, and more particularly to measuring metabolic equivalent (NETS) levels from sensors used in adaptive rate cardiac stimulators including, but not limited to, minute ventilation sensors and accelerometers, whereby patient metabolic equivalent rates and exercise events can be tracked and monitored.
II. Description of the Related Art
In order to measure metabolic equivalents it has been necessary in the past to measure the oxygen uptake (VO2) of a patient. This is difficult to do, particularly outside of a laboratory setting, in that it is necessary to have the patient equipped with respiratory monitoring devices, such as a breathing mask and sample tube, a gas analyzer, ekg leads, an electronics module for processing the parameters being monitored, etc.
Some models of calculating metabolic equivalents are based on the patient's intrinsic heart rate, but chronotropically incompetent pacemaker patients, of course, need a different model.
A method is therefore needed to monitor a patient in order to provide a physician with METS data and exertion levels, during the patient's normal living activity, without performing difficult exercise-based, oxygen uptake measurements. The measurements taken are needed to assess the lifestyle, exertion level, exercise capacity, cardiovascular functional capacity, quality of life and wellness of a patient for overall therapy management.
A method is also needed for changing the pacing parameters of a pacemaker based on current METS.